Orthopedic appliances have been increasingly used in both children and adults for correcting improper alignment of the teeth. The known orthodontic appliances, which are molded to accurately conform to the teeth and jaws of the individual user, have proven to be especially valuable in correcting malocclusions such as overbite and underbite, and open bite, where the upper and lower incisors do not contact one another.
It is also known in the fabrication of orthopedic appliances for use in closed bite cases, the typical first step is to obtain what is commonly termed a “construction bite” and/or occlusion. The occlusion is corresponded to the proper alignment of the jaw and teeth with the finished orthopedic appliance in position within the patient's mouth. As known, that in order to achieve the optimum correction of the misalignment, it is required that the occlusion be obtained as accurately as possible. When an accurate construction bite has been obtained a wax mold inserted between the posterior teeth will be imprinted with such construction bite, and can thereafter be used in the fabrication, such as by molding, of the finished orthopedic appliance.
In obtaining occlusion, dentists and dental technicians have sometimes relied on visual sighting and manual manipulation of the jaws to properly align the teeth. Additionally, some dentists have used tongue depressors inserted between the upper and lower incisors to achieve proper spacing therebetween, together with visual alignment of the midpoints of the upper and lower incisors. That is, with an increasing number of orthodontic appliances, the upper and lower incisors must be spaced apart to accommodate biting surfaces of the appliances themselves, thereby requiring accurate vertical, horizontal, and rotational alignment of the teeth preparatory to the construction bite. Although visual sighting of the midline of the upper and lower incisors have proven satisfactory in achieving rotational alignment, such method, whether alone or in combination with manual manipulation of the jaws, has not proven satisfactory in achieving accurate horizontal and vertical alignment.
For example, the bite-taking device disclosed in U.S. Pat. No. 4,439,147 provides the registration of the occlusion. This device includes an elongated handle having a ridge running from its outer end to its inner end, an enlarged portion, biting panel, and stops. The enlarged portion and stops have curved surfaces corresponding to the curvatures of the incisors and generally extending the width of the incisors. Biting panel extends a length in excess of the thickness of the incisor teeth, i.e., the length from enlarged portion to stops. Surfaces of stops are adapted to abut the rear portions of the upper and lower incisors whereas in its alternate use surfaces or enlarged portion are adapted to abut the outer surfaces of the upper and lower incisors. The biting panel is inserted into the patient's mouth and brought upward against the upper incisors just in front of one of the stops. The patient is then directed to gently bite down until the lower incisors contact the undersurface of biting panel, after which the handle is pulled gently outwardly to bring the upper and lower incisors into abutting relationship with stops, while at the same time visual sighting is made of the upper and lower incisors to achieve accurate midline adjustment. The surfaces of stops have been brought into abutting relationship with the inner surfaces of the upper and lower incisors.
The temporomandibular joint articulates the mandible to the temporal bone of the skull. If the dental patient portion of the temporomandibular joint is misaligned or if the joint or the interposed disc is damaged or destroyed pain and altered function may result. One technique used to relieve joint pressure and reposition the members of the joint involves the construction of a removable intraoral appliance or splint into which the upper and lower teeth fit in such a manner as to realign and reposition the members of the temporomandibular joint in an attempt to relieve joint pressure, provide relaxation of the jaw muscles and allow healing of the joint.
A splint is typically molded from a thermoplastic or thermosetting polymer and contains on its upper and lower surfaces a reverse image or impression of the upper teeth and the lower teeth. Stone models or casts are made from these impressions of the upper and lower teeth. These casts must then be positioned or registered relative to each other so as to achieve a desired relationship in the temporomandibular joint. As known, the splints have been made by first taking separate impressions of the upper and lower teeth utilizing conventional techniques. An intraocclusal bite record is then usually made by placing a relatively thin sheet of wax or other bite registration material between the patient's teeth and having the patient bite in the desired jaw relationship. This procedure involves a separate step utilizing the registration material which is subsequently interposed between the dental casts or models of the teeth to align the models in the desired relationship. This conventional step of relating dental casts with a separate interposed bite registration material for the purpose of producing splints, or for other occlusal therapy, introduces inaccuracies because inherent distortion of the wax or other bite registration material, especially from temperature changes, may result in an inaccurate mounting or relationship of the patient's dental casts. The multiple steps involved in handling the separate bite registration material also lead to additional distortion of the relationship between the mounted casts.
As described in the known sources, mounting the lower dental cast to the upper cast requires a separate step which is a facebow transfer. A facebow is positioned on the patient's head relative to the axis-orbital plane which relates the location of the upper dental arch to the temporomandibular joint. The facebow is then transferred to an articulator, a machine used to simulate jaw function. The model made from the impression of the upper teeth can then be positioned on the articulator utilizing the facebow. This separate step also introduces the possibility of distortion of the mounting. Thereafter, the model made from the impression of the lower teeth is positioned against the upper model using the intraocclusal bite record. Completion of these separate steps and mounting of the dental casts on the articulator yields a rigid mechanical analog of an individual's jaw movements and relationships.
For instance as known, if it is desired to make a splint in which the patient's lower jaw is moved two millimeters forward of its normally closed position to relieve pressure on the temporomandibular joint, the model of the lower teeth is moved forward relative to the model of the upper teeth and affixed at the new position. A splint is then produced from the repositioned location of the models of the upper and lower teeth. As one might surmise, this repositioning can introduce several inaccuracies into the splint. As a result, when a splint is fitted to a patient's teeth, a significant amount of time and effort may be required in order to obtain a final accurate relationship of the paired temporomandibular joints and the upper and lower teeth relative to the splint. This same registration technique described herein is applicable to recording jaw positions and relationships for fabrication of removable orthodontic appliances, for relating complete dentures, for mounting dental casts for diagnostic purposes including bite adjustments and for fabrication of single or multiple units of fixed or removable prosthetics.
The one of the known instruments by U.S. Pat. No. 4,602,905 describes the dental registration device comprising a double-sided impression tray having an anterior reinforcing enlargement through which first and second channels extend in an anterior/posterior direction. The first channel is shaped to receive a flat registration tab onto which can be positioned a deformable registration material, such as ordinary dental wax. The upper channel removably receives a reciprocator rod. A reciprocator knob threadably engages the reciprocator rod. The registration tab and the reciprocator knob coact so, that selective rotation of the knob will selectively reciprocate the registration tab in the registration channel. The impression tray has two symmetrical U-shaped ridges on the upper side of a septum and mirror image ridges extending downwardly from the lower side of the septum. The first set of ridges are spaced equidistantly from each other and with the septum define an upper impression cavity. Similarly, the lower ridges in conjunction with the septum form a lower impression cavity. The notch is extended downwardly from the upper ridge of the anterior ridge and is positioned at the anterior central end of the ridge. The flange extends forwardly from the anterior ridges adjacent the plane of the septum. The flange also extends rearwardly from the anterior ridges and lies beneath the septum. The registration channel has a rectangular cross section for receiving registration tab and the deformable registration material. The registration tab comprises a rectangular tab that slidably engages the upper surface of the registration channel and the coplanar lower surface of the reinforcement flange. The rectangular tab has an anterior extension that extends first downwardly from the anterior edge of the tab, then extends forwardly and terminates in an upwardly oriented flange. The second channel is positioned above the lower channel and has in a semicircular cross section. The posterior portion of the channel carries a downwardly extending nib, which in conjunction with an annular channel in the rod secures the rod in the channel in a predetermined position. The anterior end of the rod carries a cylindrically shaped threaded portion. Between the threaded portion and the posterior end of the rod are located a plurality of axially spaced indicia running in a circumferential direction relative to the rod. The reciprocator knob has an internal bore that is threaded to receive and engage the threaded portion of the rod.
In some construction of any rigid dental device that contacts both the upper and lower teeth, models of the patient's upper and lower dentition must be positioned on a dental articulator. It is important that they be related to each other in the same relationship as existed in the patient's mouth. Most functional orthodontic appliances are designed to keep the lower jaw forward. Therefore, the models on the articular must be positioned with the lower model forward relative to the upper model.
The most common way of transferring the dental relationship in the mouth to the articulator is with a simple wax bite. The dentist softens a block of wax with heat and inserts it between the patient's upper and lower teeth. The dentist then guides the jaw to the desired position and tells the patient to hold it there while the wax cools and hardens. The models of the patient's upper and lower teeth then can be correctly related to each other by fitting them into the indentations in the wax. The models, with the wax between them, are then attached to the articulator. This is done in a manner that will allow the wax bite to be discarded and still allow the articulator, which simulates jaw movements, to open and close back to the wax bite position.
The relationship of the mandible to the maxilla is determined by the relative positions of the incisal edges of the lower to upper central incisor teeth.
The U.S. Pat. No. 5,154,609 describes the dental bite registration device including the upper assembly incorporated the upper platform and a measuring arm. At the internal end of the upper platform is the impression platform with gripper holes to help secure the impression material on the platforms. (In this description the term “internal” refers to inside the mouth or toward the inside of the mouth, and “external” refers to outside the mouth or toward the outside of the mouth). The upper teeth indention is formed on the superior side of the upper platform by a notch which separates the upper internal block from the upper external block.
At the external end of the upper platform is the shank which connects with the measuring arm by its male portion of the snap lock. The most internal (proximal) end of the measuring arm is connected to the upper platform by its female portion of the snap lock. The most external border of the measuring arm is the measurement point which relates to the scale of the lower assembly.
The upper assembly fits within the lower assembly by inserting the measuring point in the internal (proximal) end of the channel. At the internal end of the lower assembly on the inferior side, the lower teeth indention is formed by a notch between the lower internal block and the lower external block.
The clamp, as a separate part, is either removably or permanently affixed to or near the middle of the length of the channel. The locking screw secures the anteroposterior relationship of the upper to lower assembly by compressing the measuring arm against the floor of the channel. At the internal end of the upper platform is the impression platform with gripper holes to secure the impression material on the platforms. At the external end of the impression platform is the upper teeth indention which is formed by a notch which separates the upper internal block from the upper external block. At the external end of the upper platform is the shank, which connects with the measuring arm by its male portion of the snap lock. The measuring arm is connected to the upper platform by its female portion of the snap lock. The connected measuring arm and upper platform are encased in the channel of the lower assembly in which they can freely slide anteroposteriorly. At or near the middle of the charnel is the clamp which encircles the lower assembly and the encased measuring arm. The locking screw is turned to compress the measuring arm against the floor of the channel, making it immobile.
As well known in mounting dental casts to an articulator, it is necessary to position the cast in the same relation to each other as the teeth in the patient's mouth as well as being orientated or related to the patient's hinge axis. In accomplishing that, impressions of the patient's occlusion (bite) are made in impression material positioned on a flat bite fork which is clamped between the patient's upper and lower teeth.
While the cast is held in that position, it is secured by dental plaster to a mounting plate attached to the upper frame of the dental articulator. Once the upper cast is mounted, the lower cast can be secured to the articulator by utilizing the upper cast as a guide along with an interocclusal record.
The U.S. Pat. No. 6,582,931 describes the dental-facial analyzer comprising a bite fork or plate, a pair of wings and the central portion which includes an elongated straight slot that extends forwardly from the center of the bite fork and opens to the front edge or, forward portion of the face bow. A disk-shaped holder, which includes grooves on its sides is sized to slide within the slot. The holder is formed with a central hole sized to receive a vertical indicator rod. This positions the rod perpendicular to the flat bow. One or more tubular markers slides on the upper and the lower end of the rod. A thumb screw fixes the rod relative to the holder.
The assembly also includes an upper index tray and a lower index tray. The upper index tray includes four downwardly extending pins or projections sized to fit within four mating holes formed in the bite fork. The projections are long enough such that they protrude through the bite fork and fit within four mating holes in the lower index tray. The upper index tray and lower index tray are also provided, with a number of small holes for receiving bite registration material such as impression compound. The lower frame of a dental articulator, which includes a vertical frame member topped by a pair of balls. The ball centers define a hinge axis. A horizontal lower frame member is connected to the lower portion of the vertical member and is supported on its forward end by a leg. A mounting platform assembly is mounted on a magnetic base plate secured to the lower frame member by a fastener.
While these known systems are relatively accurate, they are expensive, complex, require many different steps of the bite registration procedure, and comprise many components, the controllable means which are used for the tightening purposes (e.g. the screws to tighten), etc. As a result, many dentists (dental technicians) do not use such instruments. The most of the dental practitioners would utilize the greatly simplified dental articulator with the more simplified procedures for obtaining patient occlusion information with
Also, the bite fork of the described instruments need to be sterilized before each use.
All described prior arts are expensive and in some way have the same deficiency, that is a complexity.
Thus, there is a great need in the art for the improved not complex and not expensive device for registration of dental bite, providing simplified manufacturing (technological) process.